Field of the Invention
The present invention generally relates to an apparatus for successive supply of parts, and more particularly, is directed to improvements in a parts supplying apparatus for feeding successively relatively small parts, such as bolts or nuts used for mounting mechanical parts or components on a vehicle body, to a predetermined position from which, for example, the parts are carried to the vehicle body.
Description of the Prior Art
There has been proposed to automatize a vehicle assembly line arrangement for improving efficiency in production of vehicles. For putting automatization of the vehicle assembly line arrangement into practice, it is indispensably required to provide parts supplying apparatus for feeding automatically mechanical parts or components which are to be mounted on a vehicle body and clamping parts, such as bolts and nuts, used for fixing the mechanical parts or components to the vehicle body to various mounting stations in the vehicle assembly line arrangement.
One of the parts supplying apparatus as mentioned above, which is used for feeding relatively small parts, such as buttons to a predetermined parts gateway, is disclosed in the Japanese patent application published before examination under publication number 61-277511. In such a parts supplying apparatus as disclosed in the prior publication, a bowl structure provided on the inside thereof with a spiral guide way for guiding parts and disposed to hold the parts therein and a shooting passage disposed to interconnect therethrough the bowl structure with the parts gateway are used, and the bowl structure is vibrated for causing the parts held therein to orient to a predetermined direction on the spiral guide way and forwarding the parts caused to orient to the predetermined direction through the shooting passage to the parts gateway. The parts carried to the gateway are further transmitted by, for example, a robot to a predetermined position at which the parts are subjected to attachment or mounting. That is, if the parts are bolts for fixing mechanical components to a vehicle body, each of the bolts carried from the parts gateway is screwed through the mechanical component into the vehicle body by a screw driver or wrench.
In the case of the previously proposed parts supplying apparatus mentioned above, however, an inoperative situation in which the shooting passage is clogged with the parts which are not caused to orient properly in the shooting passage or caused to stick on the shooting passage due to friction between the parts and the shooting passage and thereby the parts are not carried to the parts gateway, arises not infrequently, and occurrence of such an undesirable situation is practically unavoidable. When the vehicle assembly line arrangement is equipped with such previously proposed parts supplying apparatus, a failure rate of the vehicle assembly line arrangement is dependent mainly upon a failure rate of each of the parts supplying apparatus and it is usual that the failure rate of each of the parts supplying apparatus determines the failure rate of the vehicle assembly line arrangement. Therefore, in the case where a plurality of parts supporting apparatus proposed previously are employed in the vehicle assembly line arrangement, it is feared that the failure rate of the vehicle assembly line arrangement is increased to a relatively large value obtained by multiplying the respective failure rates of the parts supplying apparatus.
Consequently, the parts supplying apparatus proposed previously may be excluded from a main portion of the vehicle assembly line arrangement which exerts a great harmful influence on other portions of the vehicle assembly line arrangement when the parts are stopped to be fed to the main portion and therefore the mechanical components are not mounted on the vehicle body at the main portion. By way of example, in a nut welding station at the main portion of the vehicle assembly line, in which nuts are welded on a vehicle body, it is required for a worker to confirm with his eye that each nut is fed to a welding device by a nut feeder which supplies the nut individually to be surely held by the welding device and then to have the welding device operate, so that the nut welding operation is carried out not automatically but semi-automatically and therefore efficiency in production of vehicle bodies cannot be improved.